Sorry that this is so short, it kida just happened out of the blue. I personally like Ashfur, a lot more than Brambleclaw and Squirrelflight (go ahead, unleash the hate), and I think he deserved to get a few good shots in. Hope you like.
Look at them. So happy with each other, not a care in the world. It will not be long before their poisonous blood spreads through the Clan, in the form of squealing, bouncing kits. Kits that should be mine, without the blood of that betraying, murderous tabby who is more infatuated with his own kin than with her. She and I would have been perfect together, if only I had been given a chance. But now I am left here, expected to sit and wait in the shadows until he breaks her stupid heart again. Not this time. I will have my vengeance, I'll kill them all. As soon as their kits are born, I'll slay them in front of her eyes. And then I'll kill her in the most intimate, volatile way imaginable, and her lovestruck hero won't be able to rush in and save the day once again. No, this time he'll be just a moment too late, and I will tell her that he sent me. I will leave him to the torture of living a while more, and then finish him easily, for he will be walking dead by that time. I will wipe their bloodline out of the Clan; I will cleanse and purify the cats of Thunder, and then they will kill me. So be it. I have nothing to live for, never did. It may be dishonourable, but what good is honour when you are rotting as crowfood? My soul is black and cold as ice, it will not join the noble cats in the stars. I have condemned myself to die forever, in the endless void of nonexistence. What does it matter to me? At least I will only die once. I am haunted by dreams of that void, a place with no pain, no suffering, no feeling. Eternal reprieve. And I will be there, alone. Without the tormenting gazes of those that wounded my and my heart so gravely. They will dance above, forever in the sleep of the ones left behind. His father would thank me; the tabby that bears such a remarkable resemblance to his predecessor is so different in character. So soft and spineless. It is a pity he did not turn out as brave and determined as his brother and sisters, but maybe that is why he fawns over them so much. Won't they be crushed when they find out. And not to mention her suffocatingly close family; their hearts will be broken and with time, they all will no longer be able to bear the weight of existence without their beloved princess any longer. ThunderClan will be purged, and someday they will thank me. They will worship me as the reliever of the plague the forest was fated to suffer silently through.